You can't put anything over on Chuck Shelton, a man who's coached for nearly 30 years, and his football team, the Utah State Aggies.

"We understand who we're playing," says Shelton.Sure, the 5-5-1 Aggies are on their first four-game win streak since 1978, coming off their best total-offense performance (542 yards) in Shelton's five years at USU, will post their best record since at least 1983, won five Big West Conference games for the first time and have outscored their last four opponents 182-78.

But . . . "We know who we're playing," Shelton reiterates.

They're playing BYU. Saturday. Noon. At BYU. No. 4-ranked BYU. A BYU that's probably better than that No. 4, says Shelton. A BYU that's better, in Shelton's opinion, than the 1984 Cougars who were national champions.

"There's nothing to make anyone think we'd have a chance," Shelton says, in all honesty.

And, honestly, the Aggies could lose and still have this considered a respectable season by many.

So they go in with nothing to lose. Right?

Don't say that around Shelton.

"We have a lot to lose," he shoots back. "Any time you lose a game, you've lost something. Losing would not be a happy situation. We do have an awful lot to gain," he adds.

"We go in with the attitude that, if certain things happen, we can win," Shelton says.

Foremost among those things probably is to have perfection in the offensive and defensive game plans and proper execution of those plans on the field. The Ags did stuff like that at Fresno (24-24 tie) and at San Jose (34-27 loss). Both times, they played favored opponents to a standstill. Of course, neither team was BYU, but both have at least been nationally ranked.

The key to the Aggie game plans will be variety on both offense and defense.

Defensive coordinator Fred Bleil blames the closeness (51-45) of last week's game against Pacific on his own conservative play calling the second half. "We'll have to gamble more and make more big plays," he says. "We've got to attack. We'll have multiple calls ready."

But the Aggies can't blitz every play. The Cougar line's too good to allow that, Shelton says. The element of surprise is the only hope.

On offense, "If you try to do one thing on BYU, they'll stuff you pretty good," says offensive coordinator Pat Behrns, who's had a knack for calling for halfback and receiver passes and reverses at the right times except for a bad tight-end-around last week.

The Aggies do have balance. Ron Lopez passed for 328 yards and four touchdowns last week, and his pass efficiency rating of 119.54 is up to 24th nationally. Tracey Jenkins has a school-record 13 TD catches. Roger Grant (218 yards last week) ranks fourth nationally with a 131.9-yard average and has 1,319 yards this season. He's 23rd nationally in all-purpose running.

Deception's a must because BYU's defensive line is so outstanding. Missouri and Oregon had good, big lines. Behrns says, "I don't know if any of those Oregon guys could play (at BYU)."

Lopez's throws, Shelton hopes, will keep BYU's linebackers in coverage and out of the line so Grant can run. "If you're not multifaceted, they'll really shut you down," Shelton says.

"We have to run to keep them from T-ing off on Lopez," says Behrns.

"We'll have to hope our running backs are short enough BYU's guys can't see 'em," says Behrns. Grant is 5-foot-8, and Floyd Foreman is 5-9.

AGGIE PERSONNEL - Defensive lineman Joe Jacobs has been reinstated after missing a game for a violation of team policy. Cornerback Greg Haynes practiced some this week and will at least be in uniform. Offensive lineman Joe Moore will not.